A Russian human rights council recommended Wednesday that prosecutors take action to get former oil tycoon Mikhail Khodorkovsky's conviction overturned.

Khodorkovsky has been imprisoned since his arrest in 2003 on charges widely seen as punishment for challenging Vladimir Putin, who was president at the time. A Moscow court last December found him guilty of embezzlement in a second case and ruled to keep him behind bars until 2016.

The rights council under President Dmitry Medvedev issued a report pointing to "fundamental violations" in Khodorkovsky's second trial, state news agencies reported. The council urged the prosecutor general to petition to get the verdict annulled and for investigators to review the case.

Tamara Morshchakova, a council member and a former Constitutional Court judge, told Russian news agencies that authors of the report found "no evidence or substance behind the accusations of embezzlement" leveled at Khodorkovsky in the second case.

Morshchakova described the verdict as "fictitious."

The council's decisions are not binding. The council, staffed with respected public figures, has given voice to an array of public concerns and has pushed authorities to investigate allegations of abuse and violations of the law, but its recommendations have rarely yielded tangible results.